The present invention relates to status indicating illuminative devices and more particularly to an energizing circuit for a pilot light that is designed to be considered as intrinsically safe so it may be mounted in areas considered hazardous.
The requirements of intrinsically safe devices and wiring of such devices generally are expressed in the National Electric Code as follows:
Equipment and associated wiring approved as intrinsically safe may be installed in any hazardous location for which it is approved and the provisions pertaining to conventional explosion proof procedures need not apply to such installation. Intrinsically safe equipment and wiring is incapable of releasing sufficient electrical energy under normal or abnormal conditions to cause ignition of a specific hazardous atmospheric mixture. Abnormal conditions will include accidental damage to any part of the equipment or wiring, installation or other failure of electrical components, application of over-voltage, adjustment and maintenance operations and other similar conditions.